A.  Disassembly of Stop Valves for Inspection and Repair

Caution: Before any attempt is made to disassemble the valve, verify that the valve is isolated from system pressure and secured against accidental pressurization. Follow standard tag out saftey procedures before proceeding.

NOTE:  VALVE WITH SIZE CODE 8 and 10 HAVE HANDLE & ADAPTOR (IMPACTOR HANDLE)

1. Completely remove the clampbolt from the yoke and screw it into the opposite (threaded) side of the clampbolt lug. Place a metal flat (like a fender washer) into the yoke split to stop the clampbolt. Tighten clampbolt, using it as a jacking screw, until the yoke split expands by 1/16" (this is to relieve yoke thread friction).
2. Unscrew the yoke, using a Conval Yoke Wrench. Remove the yoke assembly carefully so that the stem and disc do not scratch the bonnet sealing surface. If the bonnet becomes stuck in the body, proceed with steps 3-5 and use a small wedge under the bonnet flange.
3. Remove lock nut, washer, and valve handle.
4. Remove the check nut. After removing the check nut thread off the indicator sleeve.
5. Removal of the stem from the yoke assembly requires threading the stem down through the yoke bushing. To make removal easier it is helpful to clean the stem threads thoroughly with a wire brush and solvent. Some filing may also be required to clean the threads at the handle flats.
6. Remove timing shims (if supplied) from bonnet. Shims are provided in some valves to maintain proper yoke orientation. Keep the original shim set with the valve for reassembly.
7. To remove bonnet, invert stem and press bonnet down over stem.
8. Inspect the condition of the sealing surfaces for damage:
       *  Body:      Seat, Bonnet seal
       *  Stem:      Disc sealing surface, packing sealing surface, backseat lip of retainer
       *  Bonnet:   Backseat nose, body seal, packing chamber surface
       *  Venturi :  Sseat and venturi

B.  REPACKING

1. Remove old packing using a soft dowel (wood, plastic or brass). Put bonnet on table upside down and press rings out from the bottom. It's helpful to soak the bonnet and packing in solvent to loosen packing before removal.
   WARNING: Do not use a standard packing puller. It will cause scoring of the bonnet chamber and create a leak path.
   
   FIGURE C
   
   
   
   
2. Clean bonnet chamber in clean solvent to remove contaminants which will contribute to stem pitting. Place the bonnet chamber over the spindle of the Conval repacking tool, adding rings individually and manually depress them into the chamber with the compressing sleeve. No preloading is required. The order of assembly is as shown in Figure C (above).

NOTE:  Use only dieformed graphitic seal rings and woven graphitic wiper rings for best packing performance. See below for correct size.

Repacking Tool	Size Code	Packing Rings		Wiper Rings
		OD x ID x HT	Qty	OD x ID x HT	Qty
T5-RP-1	5E 5F 5G	1 x 5/8 x 3/8	2	1 x 5/8 x 3/16	2
T7-RP-1	7F 7G 7H 7J	1-1/4 x3/4 x1/2	2	1-1/4 x3/4 x 1/4	2
T8-RP-1	8G 8H 8J 8K	1-3/8 x 7/8 x 1/2	2	1-3/8 x 7/8 x 1/4	2
T9-RP-1	10J	1-3/4 x 1-1/8 x 3/8	3	1-3/4 x 1-1/8 x 5/16	2
T10-RP-1	10K 10L 10M	1-7/8 x 1-1/4 x 5/8	2	1-7/8 x 1-1/4 x 5/16	2

C.  SEAT/ORIFICE REPLACEMENT

1. Disassemble valve (see Disassemble section above).
2. Insert hex bar into seat/orifice insert. (See Table 4 for hex size) Attach wrench and unscrew counter-clickwise.
3. Remove old seat/orifice insert from the valve.
4. Remove old metal o-ring from the valve.
5. Screw yoke collar onto body threads and hand tighten.
6. Inspect o-ring seating area and threads to make sure they are clean.

D.  DISC

If the disc sealing surface or needle is damaged the stem assembly will need to be repaired or replaced. To repair the disc, chuck the retainer portion of the stem assembly in a lathe and center to within .001". Usa a single point carbide tool (Kennametal Grade K68 or equal) with a fine feed and cutting speed of 30-50 S.F.P.M. Machine the minimum amount of metal necessary to clean the surface to 29° ± 10 min.

E.  BONNET SEAT REFACING

1. Assemble Bonnet Lapping Tool as shown in Figure D (below).
2. Apply a small amount of Lapping Compound to the seating surface of the Bonnet Lapping Tool. Use compound 120 (coarse) for rough lapping, 280 (fine) for final lapping.
3. Apply slight downward pressure on the Bonnet Lapping Tool. Lap back and forth until a smooth finish on the Bonnet lip is achieved.
4. Clean parts thoroughly with solvent and a clean rag.

F.  REASSEMBLY

1. Clean all parts thoroughly with cleaning solvent.
2. Coat body/yoke threads with a nickel anti-seize lubricant.
3. Assemble the components in the following order:
   

a.  Use repacking tool sleeve to hold packing inside of the bonnet chamber as bonnet is slid onto stem assembly.

b.  Screw packing gland to its highest point on the yoke bushing.

c.  Replace timing shims (if shims were provided originally) onto bonnet chamber and screw stem assembly into yoke to mid travel position. Keep timing shims flat on bonnet ledge.

d.  Lubricate o-ring shoulder on seat/orifice insert and slide on a new metal o-ring. Lubricant should be low temperature and is used to hold o-ring in place during assembly.

e.  Screw in seat/orifice insert (clockwise), with new metal o-ring attached, using hex bar (see Table 4 for hex size). Tighten firmly approximately 100, 125, and 200 Ft. Lbs for the 7G, 8H, and 10K respectively. Replace the indicator sleeve, with the valve in the closed position, by screwing it back on the stem, making sure that the bottom of the indicator sleeve is reseting at "0" on the indicator tag. Then screw on the check nut. The check nut should be snug, to lock the indicator sleeve in place.

f.  Use clampbolt to spread yoke as described in step 1 of repair section. g.  Screw yoke onto body. Insure that stem is in mid travel and gland is at top of yoke bushing. Apply torque as specified in Table 2. DO NOT OVER TORQUE! h.  If yoke alignment must be changed add .030" thick shims for each 90° of desired rotation.

i.  Return clampbolt to normal position and tighten per Table 2.

j.  Place handle and fasteners onto stem and tighten.

k.  Cycle valve several times to seat packing and readjust packing gland. Tighten packing gland per Table 3 (below).